The present invention relates to a resilient support arrangement for shaft bearings of high-speed rotors. More specifically, the present invention relates to a resilient support arrangement for shaft bearings of high speed rotors for turbo machines in which the resilient support includes spring bars.
In the case of relatively small high-speed turbo machines, in particular turbochargers with their extremely high speeds of rotation, it is necessary to attenuate the dynamic forces which act during operation on the bearing of the rotors. That is forces due to vibrations of the internal combustion engine and due to possible imbalances are generally dissipated by resilient and damping elements provided between the bearing and the casing, it being possible for the resilient elements and damping elements to be separate from one another or to be combined with one another. The present invention, however, relates only to the resilient elements of the bearing support arrangement.
Resilient annular spring packs which are assembled from corrugated concentric sheet metal sleeves, are known for this purpose. However, because of their strongly progressive spring characteristic, resilient annular spring packs do not represent the optimum, especially for large turbochargers, since in this case an inadmissably large proportion of the spring travel is sacrificed by the rotor weight alone. Although the friction between the individual sheet metal sleeves ensures a certain desired damping, this also entails undesired wear phenomena.
Bar-shaped bearing support arrangements are also known from the aircraft engine construction. In these arrangements, long axial resilient bars are present between the bearing and casing and are distributed around the periphery of the bearing, one end of the bars being anchored on the casing and the other end being anchored to a bearing sleeve which receives the ball-bearing outer race. As a result, these bars exert a moment on the casing when transverse displacement of the bearing occurs. In addition, this type of construction requires a relatively large axial installation space, so that it is not particularly suitable for relatively small turbo machines, in particular for turbochargers.
The present invention is intended to avoid the disadvantages of the known bearing support arrangements. In particular, it is intended to avoid a reaction of a moment on the bearing and to be suitable for small turbo machines. In addition, the present invention is suitable for enlarged turbochargers in which a support of such a type can be accommodated in a casing in a space-saving manner.
The present invention relates to a resilient support arrangement for shaft bearings of high speed rotors. The support arrangement includes an inner strap, an outer strap and a plurality of bending spring bars arranged around the periphery of the two straps. The spring bars extend parallel to the common axis of the two straps and are joined to the inner and outer straps. The bending spring bars have a shape such that an annular gap is present between the two straps.